A catch-all functionality that is activated for a given email mailbox will permit you to receive emails that are sent to addresses that do not really exist. Otherwise said, if you deactivate an email address and somebody still sends an email message to it, or to any mistyped address under the exact same domain name, you’ll receive the email in the catch-all mailbox. Using this feature implies that you won’t miss an email for any reason, which could be crucial in case you are running some business, for instance. Since you may start receiving spam emails, you can combine the catch-all option with anti-spam filters in order to get only real emails in your inbox. Only one mailbox per domain name can be a catch-all one and email forwarding cannot be activated for a catch-all mailbox.